Large-Scale Grazing Systems
Large-scale grazing systems, as a concept for managing conservation-worthy open landscapes with megaherbivores (bison, aurochs (= “Ur”), wild horses, etc.), originated in the Oostvaardersplassen in the Netherlands. Here, a 5,600-hectare, predominantly wet area was taken out of use and, starting in 1992, managed to maintain an open landscape for endangered, predominantly ground-nesting bird species through year-round, unmanaged grazing with released red deer, Heck cattle, and Konik horses (https://de.wikipedia.org/wiki/Oostvaardersplassen). This successful approach to maintaining high nature value-grasslands, agriculturally unproductive, and often wet areas was adopted in Germany starting in the early 1990s, initially for the post-restoration management of floodplains, such as in the Lippeaue through ABU Soest (www.abu-naturschutz.de/betreuungsgebiete/hellinghauser-mersch), and also on large, former military sites (Bunzel-Drüke et al. 2008). These areas are particularly notable for their abundance of endangered species that have disappeared from intensively used agricultural landscapes (Bunzel-Drüke et al. 2019).
Large-scale grazing systems aim to allow (large) grazers (horses, cattle) to graze freely year-round on an area as large as possible, with very low stocking densities of 0.4 to 0.6 livestock units per hectare (LU/ha), typically in species-appropriate herd structures. Due to the low density, the areas are undergrazed in summer, providing suitable reproductive spaces for grazing-sensitive species. With minimal but animal-welfare-friendly supplementary feeding in winter, the grazing animals consume everything, including unpalatable, dead vegetation, maintaining the open grassland character (www.bundewischen.de, Bunzel-Drüke et al. 2008). According to the "intermediate disturbance hypothesis" from ecology, species richness in most habitats is highest under moderate disturbance levels. This approach creates species-rich open landscapes, with transitions ranging from intensively grazed areas to nearly ungrazed forested zones (www.weide-projekte-hessen.de, Brunzel-Drüke et al. 2019).
Nature Conservation,, like other fields, are influenced by changing trends, traditions, and, in part, dogmas. Grazing for the protection of high nature value cultural landscapes was long viewed critically, as grazing-sensitive species, such as orchids, could be negatively affected (cf. Kaule 1986, Plachter 1991). Only when studies showed the importance of e.g. migratory sheep herds and shepherding for the spread of species and genetic exchange between isolated protected areas (cf. Fischer et al. 1996) did grazing become "en vogue" for the protection of species-rich habitats in Germany.
Today, numerous case studieshave shown the significant advantages of large-scale grazing systems, when professionally managed, for the protection of cultural landscape-habitat types and various grazing-sensitive species, although not all species are positively affected (cf. Brunzel-Drüke et al. 2019). For example, long-term monitoring has shown that even grazing-sensitive species like the large blue butterflies Phengaris nausithous and P. teleius can be sustained with stocking densities exceeding 0.6 LU/ha (Bluth et al. 2020). However, for other grazing-sensitive species like the Globe Flower (Trollius europaeus), extensive grazing, even within the framework of conservation programs, remains a challenge (Kowarsch et al. 2022).
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Sources
Bluth, T., Erber, K., Jessat, M., Brunzel, S. (2020): Year-round large pasture grazing: Effects on populations of the large blue butterflies Phengaris nausithous and Phengaris teleius. Conservation and Landscape Planning 52: 548-590.
Bunzel-Drüke, Böhm, C., Finck, P., Kämmer, G., Luick, R., Singer, E., Riecken, U., Riedl, J., Scharf, M., Zimball, O. (2008): "Wilde Weiden" – Practical Guide to Year-round Grazing in Conservation and Landscape Development. Arbeitsgemeinschaft Biologischer Umweltschutz im Kreis Soest (ABU), Bad Sassendorf-Lohne.
Bunzel-Drüke, M., Reisinger, E., Böhm, C., Buse, J., Dalbeck, L., Ellwanger, G., Finck, P., Freese, J., Grell, H., Hauswirth, L., et al. (2019): Natural Grazing. Year-round Grazing in the Management of Habitat Types and Species in the European Natura 2000 Protected Area System. 2nd revised and expanded edition. Publisher: Arbeitsgemeinschaft Biologischer Umweltschutz im Kreis Soest e.V. (ABU). Bad Sassendorf-Lohne.
Oostvaardersplassen Wikipedia page.
Kaule, G. (1986): Species and Habitat Conservation. Verlag Eugen Ulmer. Stuttgart: 461 pages.
Kowarsch, N. R., Ziegenhagen, B., Liepelt, S., Mengel, C., Titze, A., Wrede, K., Fichna, N., Schubert, W. (2022): Ex-situ/In-situ Conservation Measures for Endangered Populations of the Globe Flower at its Northwestern Distribution Edge. Conservation and Landscape Planning 5: 157-168.
Plachter, H. (1991): Conservation. Verlag Eugen Ulmer. Stuttgart: 463 pages.